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Electrical issue

Muddytazz

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Dome light circuit, how does this work. Which wire is hot with the dome light switch off and which is hot with it on. Fighting no dome lights
 
IIRC it's orange and white, orange is likely hot.

The door jamb switches are tied into it, if those aren't working right they can mess with the dome light, even though the headlight switch turned all the way counterclockwise SHOULD force the lights on.

I might have a chance to check mine tonight under various conditions and post up.

But I will go out on a limb and say that 90%+ of the time the door jamb switches are the culprit of dome light issues.

My drivers door switch isn't working, but I believe the headlight switch still turns the domelights on, I'll doublecheck.
 
Forgot my multimeter is dead. :( I'll check the headlight switch though. Even with a dead drivers door switch, I think the domelight still works through the switch.

Does yours work with the headlight switch?

You know the bulb(s) is good?
 
Ok, found out my problem. First was a shorted out wire under the drivers seat mounting bolt to the floor. Then where the bulbs plug into the socket, there was oxidation/corrosion. Fixed the shorted out wire and cleaned up the bulb prongs and the dome lights now work.
 
On to my next electrical gremin.....Fuel gauge.

Cleaned up the ground on the frame since that is usually the most common problem and still not reading correctly. It reads I have fuel, just sometimes it reads a good 1/2" or more past the full line, or in the middle. It seems to me that it basically reads whatever it wants to read whenever it wants to read it.
 
FWIW, GM fuel gauges read about 3/8" past the full mark with a full tank.
 
Yeah I know that part, also read well below empty actually before they are empty. This one is reading at the 3 o'clock position.
 
Ok, with the blazer key in the "on" position, I disconnected the gauge wire at the plut above the rear axle and it reads at the 3 o'clock position. When I ground out the pink wire for the gauge, the needle moves to the 1/4 full mark. I've cleaned the ground wire connection really good at the frame and still get the same readings. Any ideas now?
 
If it's not pegging out the opposite way, you need to start working back towards the gauge. I'd be suspicious of the instrument panel connector.

You beat me to the dome light. :) I checked mine. If your *drivers* door switch is bad, the dome lights won't work even if the headlight switch is fully counterclockwise.. However the floor bulb (above the transmission tunnel under the dash) WILL work with the headlight switch even if the drivers door switch is bad.
 
Still working on the fuel gauge issue, but on the dome light thing. Both my door jamb switches are bad and my dome lights work off the rotation of the headlight switch.
 
Ok, traced all the wires from the plug near the tank clear to the connector at the panel. Ended up changed out the gauge and the circuit board ribbon on the back, cleaned up the connector pins(didn't look bad but did it anyways). Did the grounding out of the plug again and in "on" still goes to 3 o'clock, and when grounded, this time goes to a needle thickness below the "E".
 
Still working on the fuel gauge issue, but on the dome light thing. Both my door jamb switches are bad and my dome lights work off the rotation of the headlight switch.

Since the drivers door switch does double duty apparently, it may be that if only one wire/connection is bad, then the dome would still work. My dome works with the passenger door opened, so I know the dome circuit isn't bad.

Still sounds like the gauge isn't going far enough, but check it with fuel and see what happens. Don't have to put anything back together in the dash to have it work really, so it's pretty easy to do.
 
Still think it should "peg" the opposite direction. To be honest I've not done this enough times to see if there is any variation in gauge response to this test, but there shouldn't be.
 
I just need to get under there and drop the tank and pull the sender so I can put an ohm meter to it.
 
True, doesn't hurt to inspect the sender/tank, plus you can clean the sender "rheostat" (if thats the right description) to make sure that's not an issue either.
 
If it's not pegging out the opposite way, you need to start working back towards the gauge. I'd be suspicious of the instrument panel connector.

You beat me to the dome light. :) I checked mine. If your *drivers* door switch is bad, the dome lights won't work even if the headlight switch is fully counterclockwise.. However the floor bulb (above the transmission tunnel under the dash) WILL work with the headlight switch even if the drivers door switch is bad.
Not sure where you got this idea, but my driver's door switch is bad and my dome lights work throughout.

It is important to remember that the dome system is a ground switched system. It is always hot, the door switches and the headlight switch provide ground to the system. Any switch can fail and the others will still work.
 
I got it from my truck! I went out there and opened the drivers door with bad switch. No dome light. Use the headlight switch, and the floor lamp only works. Open the passenger door and the switch turns on ALL the interior lights, as the headlight switch and door switch should.
 
At that point I would start to blame PO's, just knowing how that system works. Basically all three switches connect to a common wire under the dash, then feed out to the footwell light and the domes. The footwell light draws power from the cigarette lighter feed, while the domes are connected to the fuse block battery feed. When I first got mine I had to replace both wires under the drivers side threshold panel, then the domes would work. But my driver's door switch has never worked, and my domes have always turned on since then from the PS or the headlight switch.
 

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